US2478592A - Ladder - Google Patents

Description

I c. E. NY'BERG 2,478,592 LADDER 2 Shets-Sheet 1 Filed May 5, 1945 Aug. 9, 1949.

c. E. NYBERG LADDER 2 Sheets-Sheet? Filed May 5, 1945 Patented Aug. 9, 1949 LADDER Curt E. Nyberg, Chicago, Ill., assignor, by mesne assignments, to Imagineering Corporation, Chicago, 111., a corporation of Illinois Application May 5, 1945, Serial No. 592,108

1 Claim.

This invention relates to ladders and more particularly to stepladders formed of sheet metal or like sheet material.

One of the objects of the invention is to provide a ladder which can be formed of sheet metal or the like and which provides maximum strength and rigidity with minimum weight.

Another object is to provide a ladder which can be easily and quickly assembled and disassembled. With this construction, the ladder can be shipped and sold in a knocked-down condition and can easily and quickly be put together by the purchaser.

In a preferred construction, the ladder is formed with a pair of side rails and a single back upright member which may be connected to a base member, formed for two point engagement with the ground. 7

Still another object is to provide a ladder which is automatically latched in open position when it is opened. The latching is preferably accomplished by a pivoted shelf which automatically moves to ahorizontal position when the ladder is opened to hold the upright member in the desired relationship with the rails. V

A further object is to provide a ladder in which steps are detachably secured to the side rails for easy assembly and disassembly. According to one feature, mounting means are provided which hold the steps on the rails and in addition detachable fastenings may be employed to secure the'steps in place.

The above and other objects and advantages will be more readily apparent from the following description when read in connection with the accompanying drawing, in which Figure l is a perspective'view of a ladder embodying the invention;

Figure 2 is a partial perspective ilustrating an alternative method of connectingthe upright to the side rails;

Figure 3 is an enlarged partial section of the top part of the ladder;

Figure 4 is a view similar to Figure 3 with the ladder in folded position;

Figure 5 is a section on the line 5--5 of Figure 3; V

Figure 6 is an end 'view of the structure shown W The ladder, as illustrated in Figure comprises 2 a pair of side rails 10, a back upright ll pivoted between the side rails at the top of the ladder, a base member [2 supporting the upright, aplurality of steps I3 extending between the side rails and pivoted shelf 14. The side rails are preferably formed of sheet metal strips rolledat their edges as indicated at [5 to provide reinfio-rcing and gripping flanges and which may be punchedout as shown at 16 between the flanges to reduce the weight. The steps i3 are similarly formed of sheet metal strips rolled downwardly attheir edges to provide reinforcing flanges. The central portions of the steps may be perforated to reduce weight or may be roughened if desired to prevent slipping. The upright H is a single metal tube or pipe pivoted at its upper end to a bracket ll secured to the lower surface of the top step. The base member [2 is similarly formed of a metal tube bent into a U-shape and secured at its center to the lower end of the upright to support it.

Instead of securing the upright to a bracket such as I! connected to the topmost step, the upper end of the upright may be connected through a T connector to a cross tube or pipe is whose ends are received in sockets l9 carried by the side rails. Otherwise the construction of Figure 2 is substantially identical to that of Figure 1 any may be assembled'and used in the same manner. I

The shelf I4 is formed with a pair of bars or rails 2i termed of metal strips or the like connected at their outer ends by a cross-piece 22 which may be integral with the bars or rails. A shelf member 23 of sheet metal or the like is fastened to the bars at their outer ends and is adapted to lie in a horizontal position when the ladder is opened. The bars 21 are pivoted at M to extensions on a bracket 25 which is se-'- cured to the bottom of a step it adjacent the top of the ladder. The bracket, as best seen in Figures 5 and 6, is formed with spaced sides between which the bars 2| move. At their inner ends, the bars carry a head member 25 adapted to fit relatively tightly between the sides of the bracket so that when the ladder is opened the head member will engage the sides of the bracket to brace the bars against lateral movement.

A ring 21 is pivoted between the bars 2| adjacent the shelf plate 23 and slidably encircles the upright l I. As the upright is swung out the ring 21 will slide down it until the shelf reaches a horizontal position with the head '26 fitting into the bracket 25. Th's prevents further downward movement of the shelf so that the ring 21' will hold the upright H in extended position 7 as shown in Figures 1 and 3. When the ladder is folded for storage, the ring will slide up the upright H to the positionshown in Figure 4 in which the upright and the shelf both he subat 34 to :formdownwardly tapering pockets.

stantially parallel to and closely adjacent the side rails so that the ladder occupies a minimum of space.

The steps F3 are detachably secured to the side rails and for this purpose are formed as shown in Figures 7 with end flanges 28 integral with the steps. Side flanges 29 integral with the end flanges 28 may be folded inwardl to underlie the central body portion of the steps and may be secured to the s'teps by *fingers projecting through openings in the steps and peene'd over at the top of the steps. The side flanges 29 .are preferably triangular, as shown, so that they taper downwardly. If desired, the steps and the end flange may be formed with one or more :stifiening and reinforcing channels 3:.

.Tosecure the steps 'to the :side rails, mounting brackets as indicated in Figure 8 are provided. :Asshown, the mounting brackets areformed of sheetmetal having a top cross portion 32 with downwardly turned triangular side portions 33 :which are-folded back upon themselves as shook/1n T e side flanges 34 are formed with projecting lugs or fingers 35 toextend through openings in the side :rails and which may bepeened over to secure the:brackets in place. In addition, the brackets zmay berspot-welded to the side rails at one or :more points, if desired.

With the several mounting brackets secured to the side rails, the top cross portions 32 and theedges 'of the end flanges 33 will lie spaced from 'the inner surface of the side rails. The :step ma then be placed in position on the bracket with the 'end flange '28 passing between the top portion 32 and the side rail and with-the triangular flanges 29 fltting-intothe correspond ingly shaped pockets formed by the flange portions 33 and 3 s of the brackets. that this construction adequately supports the steps without any additional fasteningsbut it is preferred that a-bolt or like detachable fastening beinserted through openings 36 in the steps the topportions 32 of thebrackets to make the construction more rigid and to prevent accidental displacement of the steps.

Figure 9 illustrates an alternative bracket construction which may be used in place of the bracket of Figure 8. In this construction, the bracket is formedof sheet irnetal having a cross portion 3? adapted to lie parallel to and spaced from the side rails. Triangular end flange portionsisd are bentoutwardiy from the ends c-f-the cross portion 3'? and are bent backupon themselves at 39 to formdownwardlytapering pockets to receive the side flanges E9 on the steps. The flange .portions as ma be secured to the side .rails by projecting fingers or lugs thereon and in addition by spot-welding at one or more points, if desired. The steps may-be'assembled on the brackets of Figure 9 in much the same manner as-on .the'brackets of :Figure 8 may be held thereon by bolts or like detachable :fastenings extending through holes-M in the crossrmembers 3? and'through .complementaryholes in the side rails.

"Figure .10 illustrates another mounting con-- s'truction 'forthe steps in which the of the steps are cut on" straight and are drilled as indicated at 52. As shown in this figure, the steps maybe formed with a series of perforations '43 to reduce their weight andtoprovidearough tread .portion. v.Mounting brackets in the .form of metal .stampings .44 are provided having .flat upper plate portions '45 to underlie the endpor- It wilkbe seen tions of the steps and downwardly extending flange portions 46 to lie against the side rails. The portions it and ffi .are connected by integral web portions 4! ttrreinforce arr'd'strengthen the brackets. The flange portions 46 of the brackets are formed with openings 48. Bolts .may be extended through openings '48 and aligned openings in the side rails to secure the members 1M :upon'the side irails. In addition one or more spot-welds may be used to form a rigid perman'entconnecti'onbetween the brackets and the siderails.

In assembling the steps on these brackets, the end portions of the steps are laid over the brackets with the rolled edges thereof overlying the sides of the --brackets. Ihe top plate .p'ortions 35 are .formed with holes-49 toregister'with the holes 42 in the steps so that bolts 1orslike detachablefastenings :can easily .be inserted to secure thesteps to atheibraokets.

Still another fastening construction is shown in Figure 11 :in which .the side :rails 1E0 carry a series of .headedzriv-ets 5i to lflt into key hole slots 52 formed in an end .flange on the steps i3. The holes 452 may be formed in .a .flange similar to the flange. ZEofiEigure =7 -andiare spaced to fit over the rivets -51 to secure the steps to the side rails. In addition bolts or the like may be inserted through holes 53 inthe-stepflanges and in the side rails to :prevent accidental remva1 of the steps.

With the construction .of this invention, .the ladders may be shipped in-a.knocked-.down-.condition and vmay be easily assembled by the purchaser. To assemble the ladders, I it .is .necessary only .to attachithe steps to the .mountingbrackets which are permanently assembled on the side .rails toinserttheuprights -l=l'through-.the ring 21 and pivotally connect it to.its :bracket ll. The shelf bracket 25 )will .beinstalled rat the factory by riveting-or -the.:1ike to the @pmperone-of :the steps and'the supporting .barsll 'ofthe shelf will be pivotally connected to the b-racketsibyrivets or the like. Therefore, when thesteps are assembled to the side rails the .shelfwill bexproperly positionedso that-it is-only necessary to .insert the upright through the ring 21 andto-pivotally connect it to the bracket-11 to complete the assembly. -In the constructionof-Figure 2, the assembly may be performedinthesame manner except that the upright is .connected :to the T member in the cross-rod IB rather thanto the bracket.

When so assembled, the ladder can easily be used simply by swinging the upright away from the side rails to extend the ladder. Asexplained .above, the shelf will automatically swing :down during this operation to lockithe'ladder iincextended position.

While several embodiments .of the invention have :been shown aandi'described in "detail, :it 'will be understood that they are illustrative only and are not to 'be takemasea i'definition of fthe scope of the "invention, "reference being had .for this purpose to the appended .claim.

What is claimed is:

Aladder comprising aspair-i'of sidelrails, "a plurality of crossrmembersconnectin'g the side'rail's .-and formingssteps, ea i single upright rmem'ber pivotally connected between the side irailszadja'cent the topof theala-dderto swing toward andf-away .from the I plane of .the side railsgar bracket ron'one .of the-:cross members,-a=shelf memberipivotetl at one end tothe-brackeasneans slidablyacnnrrectirrg the shelf member 'tmthempright andzinterengag ing parts on the bracket and the shelf memher to brace the shelf member when it is in a horizontal position.

CURT E. NYBERG.

REFERENCES CITED The following referenlces are of record in the file of this patent:

UNITED STATES PATENTS Number 10 Number Name Date Brooks May 9, 1911 Dueber May 23, 1916 Kirby Nov. 25, 1919 Stegeman Jan. 1, 1924 Nalder July 7, 1925 Jacobs July 13, 1926 FOREIGN PATENTS Country Date Canada Jan. 23, 1917 Germany Jan. 7, 1908 Germany Mar. 23, 1910

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